Nephrectomy during operative management of retroperitoneal sarcoma

Background: Complete resection of a retroperitoneal sarcoma often requires removal of adjacent organs. In this study we evaluated the role of nephrectomy during operation for retroperitoneal sarcoma. Methods: Between July 1982 and July 1995, 75 of the 371 (20%) patients who underwent resection of retroperitoneal sarcoma at MSKCC underwent concommitant nephrectomy. Data concerning the reasons for nephrectomy, degree of sarcomatous renal involvement, and survival were retrospectively analyzed. Results: Fifty-four patients (72%) underwent nephrectomy during the initial resection, and 21 (28%) during a resection of a recurrent or persistent tumor. The most common reason for nephrectomy was total encasement by sarcoma (n=40; 53%), followed by dense adherence of the tumor to the kidney (n=21; 28%), and the direct invasion of the kidney by tumor (n=2; 3%). Pathology demonstrated an absence of kidney invasion in the majority of cases (55 of 75; 73%). Renal capsular invasion was present in 11 of 75 (15%), renal parenchymal invasion in 7 of 75 (9%), and renal vein invasion in 2 of 75 (3%) of cases. There were no significant differences in survival based on degree of sarcoma involvement of the kidney, tumor grade, or whether the resection was for primary or recurrent disease. The 53 patients who underwent a complete gross resection of all tumor had a significantly improved long-term survival compared to the 20 patients who did not (50% versus 20% DFS at 5 years, respectively; p<0.001). Conclusions: Decisions for concomitant nephrectomy during resection of retroperitoneal sarcoma should be based on whether this maneuver will provide a complete resection of all gross tumor, in which case the long-term disease-free survival of 50% is comparable to the reported 5-year survival of all patients with retroperitoneal sarcoma who are completely resected. Presented at the 49th Annual Cancer Symposium of the Society of Surgical Oncology, Atlanta, Georgia, March 21–24, 1996.     

Propofol Increases Contractility during α1a-Adrenoreceptor Activation in Adult Rat Cardiomyocytes

Background: The objective of this study was to identify the extent to which propofol alters intracellular free Ca2+ concentration ([Ca2+]i), myofilament Ca2+ sensitivity, and contraction of individual cardiomyocytes during activation of [alpha]1a adrenoreceptors and to determine the cellular mechanism of action.

Methods: Freshly isolated ventricular myocytes were obtained from adult rat hearts. Myocyte shortening and [Ca2+]i were simultaneously monitored in individual cardiomyocytes exposed to phenylephrine after treatment with chloroethylclonidine ([alpha]1b-adrenoreceptor antagonist) and BMY 7378 ([alpha]1d-adrenoreceptor antagonist). Data are reported as mean +/- SD.

Results: Phenylephrine increased myocyte shortening by 124 +/- 9% (P = 0.002), whereas peak [Ca2+]i only increased by 8 +/- 3% (P = 0.110). Inhibition of phospholipase A2 and phospholipase C attenuated the phenylephrine-induced increase in shortening by 84 +/- 11% (P = 0.004) and 15 +/- 6% (P = 0.010), respectively. Inhibition of protein kinase C (PKC) and Rho kinase attenuated the phenylephrine-induced increase in shortening by 17 +/- 8% (P = 0.010) and 74 +/- 13% (P = 0.006), respectively. In the presence of phenylephrine, propofol increased shortening by 40 +/- 6% (P = 0.002), with no concomitant increase in [Ca2+]i. PKC inhibition prevented the propofol-induced increase in shortening. Selective inhibition of PKC[alpha], PKC[delta], PKC[varepsilon], and PKC[zeta] reduced the propofol-induced increase in shortening by 12 +/- 5% (P = 0.011), 36 +/- 8% (P = 0.001), 32 +/- 9% (P = 0.007), and 19 +/- 5% (P = 0.008), respectively. Na+-H+ exchange inhibition reduced the propofol-induced increase in shortening by 56 +/- 7% (P = 0.001).     

Functional abnormalities of experimental autogenous vein graft neoendothelium.

When a vein is grafted into the arterial circulation, the endothelium of the graft is damaged. Regeneration of an intact neoendothelium occurs, but the functional properties of this surface have not been clarified. In this study, the functional integrity of the neoendothelium of veins grafted into the carotid artery of the rabbit was assessed through the use of acetylcholine and histamine to stimulate the production of the important endothelium-derived relaxing factor (EDRF). Control veins, precontracted with norepinephrine [10(-5) M], relaxed after exposure to acetylcholine [( 10(-7) M], 42.4% +/- 6.4%, p = 0.008) and histamine [( 10(-6) M], 30.6% +/- 4.3%, p = 0.03). This relaxation response was abolished after mechanical removal of the endothelium. By contrast, neither acetylcholine nor histamine caused an endothelium-dependent relaxation in the vein grafts, even though scanning electron microscopy demonstrated the presence of a morphologically intact endothelium. However, addition of stabilized EDRF purified from cultured endothelial cells induced relaxation of the vein grafts (35.8% +/- 3.6%, p = 0.002). These data indicate that vein graft endothelium is unable to produce EDRF in response to exposure to acetylcholine or histamine. The inability to produce this potent smooth muscle cell relaxing factor and anti-aggregatory substance may be a predisposition to vein graft failure.     

Meniscal suture: a simple method

A simple technique of meniscal suture is described. It avoids the main problem with most other outside-to-inside suture techniques, which is that knots either have to be left inside the joint or have to be pulled out through the meniscus. These knots often come undone or damage either the joint surface or meniscus. Essentially, a suture is inserted from outside to inside through the meniscus, using a cannulated needle. The end of this suture is then pulled back out through a separate hole in the meniscus, using a suture loop inserted with another cannulated needle. The two ends of the first suture are then tied together.     

General practitioners'' views on continuing medical education.

BACKGROUND. The 1990 contract for general practitioners altered the provision of continuing medical education. AIM. This study set out to examine doctors' experiences of postgraduate education before and after the contract and their preferences for the provision of postgraduate education. METHOD. In 1991 a structured questionnaire was sent to 1959 doctors registered on the database held by the west of Scotland postgraduate office. RESULTS. An 82% response rate was obtained. Eighty eight questionnaires had to be excluded. Of 1523 respondents, 74% were entitled to study leave under the terms of their practice agreement, an increase of 15% since the introduction of the contract. When attending courses 11% reported that they always employed a locum (32% occasionally). Those who did so were more likely to be general practitioners in rural areas than in urban or mixed areas. Almost all respondents (1485, 98%) had participated in postgraduate education since April 1990. Lectures remained popular (47% of respondents indicated it was their preferred or most preferred choice) while distance learning and practice based learning were least preferred. Evening meetings and afternoon meetings were the most popular, and Wednesday and Thursday were reported to be the most suitable days for educational meetings. CONCLUSION. Organizing education for a large number of people is difficult, but individuals' preferences and difficulties have emerged which must be taken into account when doing so. In terms of attendance, postgraduate education seems to have been a success although its value in influencing quality of care is more doubtful. Perhaps the development of personal education plans may make learning more useful and relevant.     

Laser-generated acoustic emission in urological and arterial surgery

Acoustic emission from renal calculi irradiated by a pulsed dye laser was observed in vivo and investigated in vitro. A number of acoustic frequency spectra were recorded from laser exposure of ureteric calculi, calcified arterial wall and bladder tissue. Although differences were observed between spectra, these did not depend on target material. Investigations with model targets suggested that variations in acoustic emission were caused by fluctuations in the strength of the laser plasma, due to changes in the local surface absorption of laser light, and by alterations in the relative orientation of laser fibre, target and transducer. Interaction between lasers and stones is reviewed and discussed.